1. Technical Field
The present invention relates to control devices for a display device, display devices, control methods for the display device, and electronic apparatuses.
2. Related Art
A display device using the memory-property of display elements such as electrophoretic elements, electronic powder-particle elements, and cholestric liquid crystal elements has been known. A displayed image can be retained by means of the memory-property even when the power supply is stopped. On the other hand, it has been pointed out that afterimages would likely be generated in displayed images. In particular, a display device that would readily generate afterimages entails a problem in that its information protection function is deteriorated. An image that has been displayed in the past would be visually recognized due to its afterimage, such that information that should be protected may be visually recognized by a third party. For this reason, a technology has been proposed to reduce readability of an image that has been displayed in the past, even when an afterimage occurs, through overwriting a nonsensical readability inhibition image on the image that has been displayed (see, for example, JP-A-2010-210898).
However, according to the configuration in which characters including numbers, such as, a password, are displayed for identification, and then the characters are overwritten with a readability inhibition image, types of the readability inhibition images are limited, which causes problems in that the readability cannot be sufficiently reduced, and it becomes necessary to prepare a plurality of readability inhibition images separately in advance.